A few fast responses and facts about Two and Four Stroke Engines.

Many years ago when I got hooked by motorcycles, I started to
hear a lot about two and four stroke engines... It seemed there were
(and there still are) strong opinions in pro and con of each of the
engine types.

As Internet wasn't available, and as I was worried about other
aspects or motorcycle riding back then, I left that question unanswered
for a long time.

If this is your case or if your are interested in these two
kind of internal combustion engines, in the next few lines I hope to
give you a few fast answers and some resources to get more in depth
information.

Just keep reading...

Here are some facts about two and four stroke engines:

TWO STROKE ENGINES

Cycle - Two Strokes:

1. Compression (intake+compression)
   
2. Combustion (combustion+exhaust)
   

Take a look at the cycle in: http://science.howstuffworks.com/two-stroke2.htm

Advantages of two stroke engines:

• The engine fires - spark plug ignites - once every revolution of the crankshaft.
  
• They produce twice the power than four stroke engines.
  
• They are much simpler than four stroke engines. Fewer parts to worry about.
  

Disadvantages:

• You have to mix two stroke engine oil with gas, and depending on your consumption, this might be expensive.
  
• They last less. Lubrication is not as efficient as in a four stroke engine with heavy oil.
  
• Do not use gas efficiently.
  
• Pollute more.
  

FOUR STROKE ENGINES

Cycle - Four Strokes:

1. Intake
   
2. Compression
   
3. Combustion
   
4. Exhaust
   

Take a look at the cycle in: http://science.howstuffworks.com/engine4.htm

Advantages of four stroke engines:

• Last longer than two stroke engines
  
• More efficient use of gas
  
• Pollute less than two stroke engines
  

Disadvantages:

• More complicated. Many more parts to worry about.
  
• Half as powerful as two stroke engines (for equivalent engines)
  
• Fires once every two revolutions.
  

If you want to learn more about two stroke and four stroke engines,
take a look at the pages I mention above. You will find extensive
information and diagrams that will solve all of your doubts.

Well I hope this gave you some basic information and helped you answer some FAQ about two and four stroke engines! :-)

Enjoy the ride!